Barrier film for packaging

Abstract

The present invention relates to the composition, preparation, and use of multi-layer composite films comprising a core layer of low gas permeable material, two intermediate layers sandwiching the core layer, and two outer layers sandwiching the two intermediate layers. The core layer provides the excellent oxygen barrier property, whereas the intermediate and outer layers protect the core layer so the oxygen permeability of the resulting multi-layer composite film becomes independent on relative humidity.

What is claimed: 
     
       1. A process for using a multi-layer film to make a container comprising the steps of: adhering or laminating a multi-layer film on a skeletal layer and forming the skeletal layer into a package, wherein said multi-layer film is selected from the group consisting of (I), (II) and (III), where: (I) is a multi-layer film comprising: a core layer of polyvinyl alcohol,   an intermediate layer of a plastic substrate disposed on each side of said core layer, and   an outer layer of a silicone resin of sufficient thickness to protect the polyvinyl alcohol layer from moisture, said silicone resin disposed on each respective intermediate layer,     (II) is multi-layer composite film comprising: a core layer of polyvinyl alcohol,   an intermediate layer of a silicone resin of sufficient thickness to protect the polyvinyl alcohol layer from moisture, said silicone resin disposed on each side of said core layer,   an outer layer of a plastic substrate disposed on each respective intermediate layer, and     (III) is a multi-layer composite film comprising: a first outer layer of a plastic substrate,   a first intermediate layer of a silicone resin disposed on said first outer layer,   a core layer of polyvinyl alcohol disposed on said first intermediate layer,   a second intermediate layer of a plastic substrate disposed on said core layer, and   a second outer layer of a silicone resin disposed on said second intermediate layer,      wherein said first intermediate layer and said second outer layer of silicone resin is of sufficient thickness to protect the polyvinyl alcohol layer from moisture,   wherein said silicone resin of (I), (II), and (III) is derived from a silane solution selected from the group consisting of CH 2  ═CHC 6  H 4  CH 2  NHCH 2  CH 2  NHCH 2  CH 2  CH 2  --Si(OR 1 ) 3  and HCl.CH 2  ═CHC 6  H 4  CH 2  NHCH 2  CH 2  NHCH 2  CH 2  CH 2  --Si(OR 1 ) 3 , each in a water/alcohol mixture, where R 1  is an alkyl radical of from 1 to 4 carbon atoms inclusive or   wherein said silicone resin is derived from a silane solution comprising: (a) a silane having the general formula RSi(OR 1 ) 3 , where R is a methyl or phenyl group and where R 1  is an alkyl radical of from 1 to 4 carbon atoms inclusive;   (b) a solvent; and   (c) a silane having the general formula R 2  Si(OR 3 ) 3 , where R 3  is an alkyl radical of from 1 to 4 carbon atoms inclusive, and R 2  is selected from the group consisting of: (i) R 4  HN(CH 2 ) a  --, where R 4  is a hydrogen atom or an alkyl radical of from 1 to 4 carbon atoms inclusive, and a is an integer from 3 to 8 inclusive, and   (ii) H 2  N(CH 2 ) b  NH(CH 2 ) c  --, where b is an integer from 2 to 8 inclusive and c is an integer from 3 to 8 inclusive.         
     
     
       2. The process of claim 1, wherein the skeletal layer is selected from the group consisting of paper, plastic and cardboard. 
     
     
       3. The process of claim 1, wherein the plastic substrates are each polyolefins. 
     
     
       4. The process of claim 1, wherein said solvent is an alcohol. 
     
     
       5. The process of claim 1, wherein said solvent is a mixture of alcohol and water. 
     
     
       6. The process of claim 1, wherein at least one of the intermediate layers is bonded to the core layer with an adhesive. 
     
     
       7. A process for using a multi-layer film in a package comprising the step of forming a multi-layer film into a package, wherein said package is a bag or pouch, wherein said multi-layer film is selected from the group consisting of (I), (II) and (III), where: (I) is a multi-layer film comprising: a core layer of polyvinyl alcohol,   an intermediate layer of a plastic substrate disposed on each side of said core layer, and   an outer layer of a silicone resin of sufficient thickness to protect the polyvinyl alcohol from moisture, said silicone resin disposed on each respective intermediate layer,     (II) is a multi-layer film comprising: a core layer of polyvinyl alcohol,   an intermediate layer of a silicone resin of sufficient thickness to protect the polyvinyl alcohol from moisture, said silicone resin disposed on each side of said core layer, and   an outer layer of a plastic substrate disposed on each respective intermediate layer, and     (III) is a multi-layer film comprising: a first outer layer of a plastic substrate,   a first intermediate layer of a silicone resin disposed on said first outer layer,   a core layer of polyvinyl alcohol disposed on said first intermediate layer,   a second intermediate layer of a plastic substrate disposed on said core layer, and   a second outer layer of a silicone resin disposed on said second intermediate layer,   wherein said silicone resin disposed on said first and second intermediate layers is of sufficient thickness to protect the polyvinyl alcohol from moisture, and wherein the silicone resin of (I), (II) and (III) is derived from a silane solution selected from the group consisting of CH 2  ═CHC 6  H 4  CH 2  NHCH 2  CH 2  NHCH 2  CH 2  CH 2  --Si(OR 1 ) 3  and HCl.CH 2  ═CHC 6  H 4  CH 2  NHCH 2  CH 2  NHCH 2  CH 2  CH 2  --Si(OR 1 )3, each in a water/alcohol mixture, where R 1  is an alkyl radical of from 1 to 4 carbon atoms inclusive or   wherein said silicone resin is derived from a silane solution comprising: (a) a silane having the general formula RSi(OR 1 ) 3 , where R is a methyl or phenyl group and where R 1  is an alkyl radical of from 1 to 4 carbon atoms inclusive;   (b) a solvent; and   (c) a silane having the general formula R 2  Si(OR 3 ) 3 , where R 3  is an alkyl radical of from 1 to 4 carbon atoms inclusive, and R 2  is selected from the group consisting of: (i) R 4  HN(CH 2 ) a  --, where R 4  is a hydrogen atom or an alkyl radical of from 1 to 4 carbon atoms inclusive, and a is an integer from 3 to 8 inclusive, and   (ii) H 2  N(CH 2 ) b  NH(CH 2 ) c  --, where b is an integer from 2 to 8 inclusive and c is an integer from 3 to 8 inclusive.         
     
     
       8. The process of claim 7, wherein the plastic substrates are each polyolefins. 
     
     
       9. The process of claim 7, wherein said solvent is an alcohol. 
     
     
       10. The process of claim 7, wherein said solvent is a mixture of alcohol and water. 
     
     
       11. The process of claim 7, wherein at least one of the intermediate layers is bonded to the core layer with an adhesive. 
     
     
       12. A process for using a composite comprising the steps of adhering or laminating a multi-layer film on a skeletal layer, wherein said multi-layer film is selected from the group consisting of (I), (II) and (III), where: (I) is a multi-layer film comprising: a core layer of polyvinyl alcohol,   an intermediate layer of a plastic substrate disposed on each side of said core layer, and   an outer layer of a silicone resin of sufficient thickness to protect the polyvinyl alcohol from moisture, said silicone resin disposed on each respective intermediate layer,     (II) is a multi-layer film comprising: a core layer of polyvinyl alcohol,   an intermediate layer of a silicone resin of sufficient thickness to protect the polyvinyl alcohol from moisture, said silicone resin disposed on each side of said core layer, and   an outer layer of a plastic substrate disposed on each respective intermediate layer, and     (III) is a multi-layer film comprising: a first outer layer of a plastic substrate,   a first intermediate layer of a silicone resin disposed on said first outer layer,   a core layer of polyvinyl alcohol disposed on said first intermediate layer,   a second intermediate layer of a plastic substrate disposed on said core layer, and   a second outer layer of a silicone resin disposed on said second intermediate layer,   wherein said silicone resin disposed on said first and second intermediate layers is of sufficient thickness to protect the polyvinyl alcohol from moisture, wherein the silicone resin of (I), (II) and (III) is derived from a silane solution selected from the group consisting of CH 2  ═CHC 6  H 4  CH 2  NHCH 2  CH 2  NHCH 2  CH 2  CH 2  --Si(OR 1 ) 3  and HCl.CH 2  ═CHC 6  H 4  CH 2  NHCH 2  CH 2  NHCH 2  CH 2  CH 2  --Si(OR 1 ) 3 , each in a water/alcohol mixture, where R 1  is an alkyl radical of from 1 to 4 carbon atoms inclusive or   wherein said silicone resin is derived from a silane solution comprising: (a) a silane having the general formula RSi(OR 1 ) 3 , where R is a methyl or phenyl group and where R 1  is an alkyl radical of from 1 to 4 carbon atoms inclusive;   (b) a solvent; and   (c) a silane having the general formula R 2  Si(OR 3 ) 3 , where R 3  is an alkyl radical of from 1 to 4 carbon atoms inclusive, and R 2  is selected from the group consisting of: (i) R 4  HN(CH 2 ) a  --, where R 4  is a hydrogen atom or an alkyl radical of from 1 to 4 carbon atoms inclusive, and a is an integer from 3 to 8 inclusive, and   (ii) H 2  N(CH 2 ) b  NH(CH 2 ) c  --, where b is an integer from 2 to 8 inclusive and c is an integer from 3 to 8 inclusive.         
     
     
       13. The process of claim 12, wherein the skeletal layer is selected from the group consisting of paper, plastic and cardboard. 
     
     
       14. The process of claim 12, wherein the plastic substrates are each polyolefins. 
     
     
       15. The process of claim 12, wherein said solvent is an alcohol. 
     
     
       16. The process of claim 12, wherein said solvent is a mixture of alcohol and water. 
     
     
       17. The process of claim 12, wherein at least one of the intermediate layers is bonded to the core layer with an adhesive.